ML20058E071

SER Approving 900926 Request for Relief from ASME Code Inservice Insp Requirements to Repair Svc Water Sys

ML20058E071
Person / Time
Site:	Millstone
Issue date:	10/16/1990
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20058E070	List: ML20058E066 ML20058E071
References
NUDOCS 9011070011
Download: ML20058E071 (3)

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~ WUCLEAR REGULATORY COMMISSION j]

WASHING TON, D. C. 20555 f

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SAFETY' EVALUATION BY THE'0FFICE OF NUCLEAR REACTOR REGULATION

'RELATED TO PE00EST FOR RELIEF FROM ASME CODE REPAIR REOUIREMENTS s

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9-FOR ASME CODE CLASS ~3 PIPING' NORTHEAST NUCLEAR' ENERGY COMPANY.-ET Al s;-

MILLSTONE NUCLEAR' POWER STATION'-UNIT NO. 3 DOCKET'NO. 50-423 s

1 1 : BACKGROUND i

Temoorary Non-Code Repairs-

-10 CFR 50.55a(g) requires nuclear power facility piping and components to: meet 3

N the applicable requirementsiof Section XI of the' ASME. Boiler and Pressure -

Vessel Code (hereafter called the code).- Section XI of the code. specifies code'-acceptable-repair methods' for flaws that exceed code acceptance limits in :

3 piping:that is in service. A code repair is' required to restore the structural integrity :of flawed code piping, independent of the~ operational mode of the -

plant when the~ flaw. is detected. Those repairs not in compliance with Section-

'XILof~the code ~are non-code repairs.- However, tne required code repair may be'-

".w 11mpractical.: Pursuantito'-10 CFR 50a(g)(6)(ii). the Commission.will evaluate-

determinations of impracticality, and may grant relief and may impose ~ alterna-

'a tive requirements. Generic Letter 90-05,. entitled " Guidance for Performing 1

Temporary Non-Code Repair of ~ ASME Code. Class 1,:2, t.nd. 3 Piping," and dated

. June 15,1990, provides guidance-for the staff in evaluating relief requests submitted by licensees,for temporary non-code repairs of code Class 3 piping.-

i TThescommission may gran't relief based on a staff evaluation considering the guidancetin ' Generic ' Letter 90-05.

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< Licensee's Relief Reci=st

'By. letter dated September 26, 1990,, Northeast Nuclear Energy Company-(the w*

jlicensee)1requestedrelieffromccderepairrequirements-ofcertaincode i

Class 3 pipi.ng at Millstone Unit 3.. A pinhole leak was detected in the code

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Class-3 moderate energy service water system piping during plant operation.

l and the licensee.has detemined that confomance with code-repair requirements h

L, isimpractical..-Pursuant'to.10CFR50.55a(g)(5)(iii),thelicenseesubmitted La relief request to the Commission. The subject piping ~is a.6-inch expansion e

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" joint fabricated from Monel..The licensee proposed a temporary non-code repair by replacing the subject piping with one. fabricated from rubber, which

'is a non-code material.

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EVALUATION OF RELIEF REQUEST Code Reauirement Article IWA-4000 of Sectior XI of the code specifies the code repair procedures.

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,m Code' Relief-Request Relief is: requested'from performing a code repair for the flaw detected during i

f plant l operation.in code Classi3' piping.

Basis for Relief-1 Code ~ repair; requirements.are impractical because a wel.d repair cannot be

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performed on the subject expansion joint bellows and e code qualified repla:e-o "-

1 ment cannot be obtained for several months.

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. Proposed Alternative.

The licensee proposed.to-utilize the guidance in Generic Letter 90-0540 perform at temporary non-code repair..

f Staff 3 Evaluation'and Conclusions Dw ~

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The staff has determined that; code repair requirements in this case are

' impractical. ThisLis because the subject expansion joint bellows cannot be weldLrepaired;and a code qualified: replacement'is not readily available. The q

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Jdesign:of(the rubber: expansion' joint' temporary replacement 1siconsistent with D

L the originaliexpans_ ion joint. -Although-the rubber material is not a code d

L material', it is compatible for seawater-.' serviceand is not ex)ected to 1

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+.in a.few months. Furthermore, the licensee hasicommitted to the guidance

, : experience any: material degradation before..it is replaced wit1.a code repair 1

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Lprovided in Generic Letter 90-05 which will reasonably assure structural i

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Lintegrity and protect public. health and safety. Accordingly, the staff i

concludes that granting relief-where code requirements are impractical and

' imposing alternative requirements are. authorized.by law and will'not endanger lifel or property orsthe'comon' defense and; security.'and are' otherwise in' the -

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' public : interest,: given <due consideration to the burden upon the' licensee and

. facilitysthat'couldoresult?if. the. code requirements were. imposed on the p

facility.:' Pursuant to 10 CFR 50.55a(g)(6)(1) and consistent with the guidance.

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.in Generic Letter 90-05, reli_ef is: granted until the next scheduled refueling.

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5 outageL(approximately March of.1991). ' The temporary non-code repair must-then i

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.be replaced with a codeLrepair.

l:c Regulatory Issue i

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' :In.a recent NRC plant inspection, it was found that the licensee had performed

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?aitemporary non-code repair on the subject piping without prior written relief T

. granted by the Consnission. The-licensee was.not in compliance with NRC.

regulations' when. the ^ subject repair was performed. This issue will be 1

' ';g addressed :in a forthcoming.NRC inspection report.

n Principal' Contributor:

C.Y. Cheng and D. Jaffe Dated: October 16,1990

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